Defect-mitigation layers in electrochromic devices

Abstract

Electrochromic devices and methods may employ the addition of a defect-mitigating insulating layer which prevents electronically conducting layers and/or electrochromically active layers from contacting layers of the opposite polarity and creating a short circuit in regions where defects form. In some embodiments, an encapsulating layer is provided to encapsulate particles and prevent them from ejecting from the device stack and risking a short circuit when subsequent layers are deposited. The insulating layer may have an electronic resistivity of between about 1 and 10 8 Ohm-cm. In some embodiments, the insulating layer contains one or more of the following metal oxides: aluminum oxide, zinc oxide, tin oxide, silicon aluminum oxide, cerium oxide, tungsten oxide, nickel tungsten oxide, and oxidized indium tin oxide. Carbides, nitrides, oxynitrides, and oxycarbides may also be used.

What is claimed is: 
     
       1. An electrochromic device comprising:
 a substrate; 
 a first electrode layer disposed on the substrate, the first electrode layer comprising a first transparent electronically conductive material; 
 an electrochromic stack comprising an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material; 
 a second electrode layer disposed on the electrochromic stack, the second electrode layer comprising a second transparent electronically conductive material; and 
 a defect-mitigating insulating layer comprising a substantially transparent and electronically insulating material disposed at (i) a location between an intermediate position within the electrochromic layer and the position of the electrode layer to which the electrochromic layer is in most direct electrical communication or (ii) a location between an intermediate position within the counter electrode layer and the position of the electrode layer to which the counter electrode layer is in the most direct electrical communication. 
 
     
     
       2. The electrochromic device of  claim 1 , wherein the electrochromic material is a cathodically coloring electrochromic material and the counter electrode material is an anodically coloring electrochromic material, and wherein the electrochromic layer is adjacent to the first electrode layer and the counter electrode layer is adjacent to the second electrode layer. 
     
     
       3. The electrochromic device of  claim 2 , wherein the electrochromic material comprises a tungsten oxide. 
     
     
       4. The electrochromic device of  claim 2 , wherein the counter electrode material comprises a nickel tungsten oxide. 
     
     
       5. The electrochromic device of  claim 2 , wherein the electrochromic stack further comprises an ion conducting layer interposed between the electrochromic layer and the counter electrode layer. 
     
     
       6. The electrochromic device of  claim 2 , wherein the defect-mitigating insulating layer is disposed between an intermediate position within the counter electrode layer and the second electrode layer. 
     
     
       7. The electrochromic device of  claim 2 , wherein the defect-mitigating insulating layer is disposed at an intermediate position within the counter electrode layer. 
     
     
       8. The electrochromic device of  claim 6 , wherein the defect-mitigating insulating layer is disposed between the counter electrode layer and the second electrode layer, in contact with the second electrode layer. 
     
     
       9. The electrochromic device of  claim 1 , further comprising one or more layers between the substrate and the first electrode layer. 
     
     
       10. The electrochromic device of  claim 9 , wherein one of the layers between the substrate and the first electrode layer is a diffusion barrier layer. 
     
     
       11. The electrochromic device of  claim 1 , wherein the electrochromic material is a cathodically coloring electrochromic material and the counter electrode material is an anodically coloring electrochromic material, and wherein the electrochromic layer is adjacent to the second electrode layer and the counter electrode layer is adjacent to the first electrode layer. 
     
     
       12. The electrochromic device of  claim 11 , wherein the defect-mitigating insulating layer is disposed between an intermediate position within the electrochromic layer and the second electrode layer. 
     
     
       13. The electrochromic device of  claim 11 , wherein the defect-mitigating insulating layer is disposed at an intermediate position within the electrochromic layer. 
     
     
       14. The electrochromic device of  claim 11 , wherein the defect-mitigating insulating layer is disposed between the electrochromic layer and the second electrode layer, in contact with the second electrode layer. 
     
     
       15. The electrochromic device of  claim 1 , wherein the electrochromic stack does not contain a separately deposited ion conductor layer. 
     
     
       16. The electrochromic device of  claim 1 , wherein a number of visible short-related pinhole defects in the electrochromic device is no greater than about 0.005 per square centimeter. 
     
     
       17. The electrochromic device of  claim 1 , wherein in the electrochromic stack is entirely solid state and inorganic. 
     
     
       18. The electrochromic device of  claim 17 , wherein the electrochromic layer comprises two sub-layers each comprising tungsten oxide, and wherein one sub-layer has a greater concentration of oxygen than the other sub-layer. 
     
     
       19. The electrochromic device of  claim 17 , wherein the counter electrode layer comprises a nickel tungsten oxide. 
     
     
       20. The electrochromic device of  claim 1 , wherein the defect-mitigating insulating layer comprises a metal oxide, a metal nitride, a metal carbide, a metal oxynitride, or a metal oxycarbide. 
     
     
       21. The electrochromic device of  claim 20 , wherein the defect-mitigating insulating layer comprises a metal oxide selected from the group consisting of aluminum oxide, titanium oxide, tantalum oxide, cerium oxide, zinc oxide, tin oxide, silicon aluminum oxide, tungsten oxide, nickel tungsten oxide, and oxidized indium tin oxide. 
     
     
       22. The electrochromic device of  claim 20 , wherein the defect-mitigating insulating layer comprises a metal nitride selected from the group consisting of titanium nitride, aluminum nitride, silicon nitride, tantalum nitride, and tungsten nitride. 
     
     
       23. The electrochromic layer of  claim 20 , wherein the defect-mitigating insulating layer comprises a metal carbide selected from the group consisting of titanium carbide, aluminum carbide, silicon carbide, tantalum carbide, and tungsten carbide. 
     
     
       24. The electrochromic device of  claim 1 , wherein the defect-mitigating insulating layer is between about 5 nm and 500 nm in thickness. 
     
     
       25. The electrochromic device of  claim 1 , wherein the electrochromic stack has a graded composition. 
     
     
       26. The electrochromic device of  claim 1 , further comprising a second defect-mitigating insulating layer proximate the first electrode layer. 
     
     
       27. The electrochromic device of  claim 26 , wherein both defect-mitigating insulating layers are disposed between the first and second electrode layers. 
     
     
       28. The electrochromic device of  claim 1 , wherein the defect-mitigating insulating layer comprises two distinct electronically insulating materials. 
     
     
       29. The electrochromic device of  claim 28 , wherein said defect-mitigating insulating layer comprises particles of a polishing compound. 
     
     
       30. The electrochromic device of  claim 1 , wherein the defect-mitigating insulating layer is ionically conductive. 
     
     
       31. The electrochromic device of  claim 1 , wherein the defect-mitigating insulating layer has an electronic resistivity of between about 1 and 10 15  ohm-cm. 
     
     
       32. A method of fabricating an electrochromic device, the method comprising:
 forming an electrochromic stack on a first electrode layer disposed on a substrate, wherein the electrochromic stack comprises an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material, and wherein the first electrode layer comprises a first transparent electronically conductive material; 
 forming a defect-mitigating insulating layer within, beneath, or on the electrochromic stack, wherein the defect-mitigating insulating layer comprises a substantially transparent and electronically insulating material; and 
 forming a second electrode layer over the electrochromic stack, the second electrode layer comprising a second transparent electronically conductive material, 
 wherein the defect-mitigating insulating layer is disposed at (i) a location between an intermediate position within the electrochromic layer and the position of the electrode layer to which the electrochromic layer is in most direct electrical communication or (ii) a location between an intermediate position within the counter electrode layer and the position of the electrode layer to which the counter electrode layer is in the most direct electrical communication. 
 
     
     
       33. An electrochromic device comprising:
 a substrate; 
 a first electrode layer disposed on the substrate, the first electrode layer comprising a first transparent electronically conductive material; 
 an electrochromic stack comprising an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material, wherein the first electrode layer is between the substrate and the electrochromic stack; 
 a second electrode layer disposed on the electrochromic stack such that the electrochromic stack is disposed between the first electrode layer and the second electrode layer, the second electrode layer comprising a second transparent electronically conductive material; and 
 a defect-mitigating insulating layer that is substantially transparent and electronically insulating, wherein the defect-mitigating insulating layer is disposed between the first electrode layer and the electrochromic stack. 
 
     
     
       34. A method of fabricating an electrochromic device, the method comprising:
 (a) receiving a substrate in sputter deposition apparatus,
 wherein the substrate includes a first electrode layer and a defect-mitigating insulating layer formed thereon, and the first electrode layer is disposed between the substrate and the defect-mitigating insulating layer, and the first electrode layer comprises a first transparent electronically conductive material, 
 wherein the insulating layer is electronically insulating and substantially transparent; 
 
 (b) forming an electrochromic stack on the substrate,
 wherein the electrochromic stack comprises an electrochromic layer of electrochromic material and a counter electrode layer of counter electrode material; and 
 
 (c) forming a second electrode layer over the electrochromic stack, the second electrode layer comprising a second transparent electronically conductive material. 
 
     
     
       35. An apparatus for fabricating an electrochromic device, comprising:
 (a) an integrated deposition system comprising:
 (i) a first deposition station containing a first target comprising a first material for depositing a layer of an electrochromic material on a substrate when the substrate is positioned in the first deposition station, 
 (ii) a second deposition station containing a second target comprising a second material for depositing a layer of a counter electrode material on the substrate when the substrate is positioned in the second deposition station, and 
 (iii) a third deposition station configured to deposit a defect-mitigating insulating layer that is electronically insulating and substantially transparent; and 
 
 (b) a controller containing program instructions for passing the substrate through the first and second deposition stations in a manner that sequentially deposits a stack on the substrate, the stack comprising the layer of electrochromic material, the layer of counter electrode material, and the defect-mitigating insulating layer. 
 
     
     
       36. The method of  claim 32 , wherein electrochromic layer comprises a cathodically coloring electrochromic material and is formed before the counter electrode layer in the electrochromic stack. 
     
     
       37. The method of  claim 36 , wherein the defect-mitigating insulating layer is formed between the electrochromic layer and the first electrode layer, in contact with the first electrode layer. 
     
     
       38. The method of  claim 36 , wherein the defect-mitigating insulating layer is formed between the counter electrode layer and the second electrode layer, in contact with the second electrode layer. 
     
     
       39. The method of  claim 36 , wherein the defect-mitigating insulating layer is formed within the counter electrode layer. 
     
     
       40. The method of  claim 36 , wherein the defect-mitigating insulating layer is formed within the electrochromic layer. 
     
     
       41. The method of  claim 36 , further comprising forming or polishing a second defect-mitigating insulating layer between the first electrode layer and the electrochromic layer. 
     
     
       42. The method of  claim 32 , wherein electrochromic layer comprises a cathodically coloring electrochromic material and is formed after the counter electrode layer in the electrochromic stack. 
     
     
       43. The method of  claim 42 , further comprising forming or polishing a second defect-mitigating insulating layer between the first electrode layer and the counter electrode layer. 
     
     
       44. The method of  claim 42 , wherein the defect-mitigating insulating layer is formed between the electrochromic layer and the second electrode layer, in contact with the second electrode layer. 
     
     
       45. The method of  claim 42 , wherein the defect-mitigating insulating layer is formed within the electrochromic layer. 
     
     
       46. The method of  claim 42 , wherein the defect-mitigating insulating layer is formed within the counter electrode layer. 
     
     
       47. The method of  claim 42 , wherein the defect-mitigating insulating layer is formed between the counter electrode layer and the first electrode layer, in contact with the first electrode layer. 
     
     
       48. The method of  claim 32 , wherein forming the electrochromic stack is performed without depositing an ion conducting layer. 
     
     
       49. The method of  claim 32 , wherein in the electrochromic stack is entirely solid state and inorganic. 
     
     
       50. The method of  claim 49 , wherein the electrochromic material comprises a tungsten oxide. 
     
     
       51. The method of  claim 49 , wherein the counter electrode material comprises a nickel tungsten oxide. 
     
     
       52. The method of  claim 32 , wherein forming the electrochromic stack comprises forming an electrochromic layer having two sub-layers each comprising tungsten oxide, but with different levels of oxygen. 
     
     
       53. The method of  claim 32 , wherein the defect-mitigating insulating layer comprises a metal oxide, a metal nitride, a metal carbide, a metal oxynitride, and a metal oxycarbide. 
     
     
       54. The method of  claim 53 , wherein the defect-mitigating insulating layer comprises a metal oxide selected from the group consisting of aluminum oxide, titanium oxide, cerium oxide, zinc oxide, tin oxide, silicon aluminum oxide, tungsten oxide, tantalum oxide, nickel tungsten oxide, and oxidized indium tin oxide. 
     
     
       55. The method of  claim 53 , wherein the defect-mitigating insulating layer comprises a metal nitride selected from the group consisting of titanium nitride, aluminum nitride, silicon nitride, tantalum nitride, and tungsten nitride. 
     
     
       56. The method of  claim 53 , wherein the defect-mitigating insulating layer comprises a metal carbide selected from the group consisting of titanium carbide, aluminum carbide, silicon carbide, tantalum carbide, and tungsten carbide. 
     
     
       57. The method of  claim 32 , further comprising depositing lithium on at least a portion of the electrochromic stack. 
     
     
       58. The method of  claim 57 , wherein depositing lithium is performed prior to forming the defect-mitigating insulating layer. 
     
     
       59. The method of  claim 32 , wherein forming the defect-mitigating insulating layer comprises forming two distinct electronically insulating materials. 
     
     
       60. The method of  claim 59 , wherein forming the defect-mitigating insulating layer comprises polishing an insulating layer on the substrate as provided to the process, and wherein one of said electronically insulating materials comprises particles of a polishing compound. 
     
     
       61. The method of  claim 60 , wherein the insulating layer on the substrate comprises titanium dioxide. 
     
     
       62. The method of  claim 32 , wherein forming the defect-mitigating insulating layer comprises polishing the first electrode layer on the substrate, and wherein said electronically insulating material of the defect-mitigating insulating layer comprises particles of a polishing compound. 
     
     
       63. The method of  claim 32 , further comprising forming a second defect-mitigating insulating layer. 
     
     
       64. The method of  claim 63 , wherein both defect-mitigating insulating layers are disposed between the first and second electrode layers. 
     
     
       65. The method of  claim 32 , wherein one or more layers are disposed between the substrate and the first electrode layer. 
     
     
       66. The method of  claim 65 , wherein one of the layers between the substrate and the first electrode layer is a diffusion barrier layer. 
     
     
       67. The method of  claim 32 , wherein the insulating layer has an electronic resistivity of between about 1 and 10 15  ohm-cm. 
     
     
       68. The electrochromic device of  claim 33 , further comprising a second defect-mitigating insulating layer, wherein the second defect-mitigating insulating layer is disposed on or in the electrochromic stack. 
     
     
       69. The electrochromic device of  claim 33 , wherein the defect-mitigating insulating layer comprises a metal oxide, a metal nitride, a metal carbide, a metal oxynitride, or metal oxycarbide. 
     
     
       70. The electrochromic device of  claim 69 , wherein the defect-mitigating insulating layer comprises a metal oxide is selected from the group consisting of aluminum oxide, titanium oxide, cerium oxide, zinc oxide, tin oxide, silicon aluminum oxide, tungsten oxide, tantalum oxide, nickel tungsten oxide, and oxidized indium tin oxide. 
     
     
       71. The electrochromic device of  claim 69 , wherein the defect-mitigating insulating layer comprises titanium oxide. 
     
     
       72. The electrochromic device of  claim 69 , wherein the defect-mitigating insulating layer comprises tin oxide. 
     
     
       73. The electrochromic device of  claim 33 , wherein the defect-mitigating insulating layer is between about 5 and 100 nm thick. 
     
     
       74. The method of  claim 34 , further comprising polishing the defect-mitigating insulating layer prior to forming the electrochromic stack on a substrate. 
     
     
       75. The method of  claim 74 , wherein the defect-mitigating insulating layer comprises particles of a polishing compound. 
     
     
       76. The method of  claim 34 , wherein the defect-mitigating insulating layer comprises a metal oxide, metal nitride, a metal carbide, a metal oxynitride,or a metal oxycarbide. 
     
     
       77. The method of  claim 76 , wherein the defect-mitigating insulating layer is a metal oxide selected from the group consisting of aluminum oxide, cerium oxide, zinc oxide, tin oxide, silicon aluminum oxide, tungsten oxide, nickel tungsten oxide, and oxidized indium tin oxide. 
     
     
       78. The method of  claim 76 , wherein said defect-mitigating insulating layer comprises particles of a polishing compound. 
     
     
       79. The method of  claim 34 , further comprising forming a second defect-mitigating insulating layer in or on the electrochromic stack. 
     
     
       80. The method of  claim 34 , wherein the defect-mitigating insulating layer is between about 5 and 100 nm thick. 
     
     
       81. The apparatus of  claim 35 , further comprising a fourth deposition station configured to deposit an electrode layer on the stack, wherein the electrode layer comprises a transparent electronically conductive material. 
     
     
       82. The apparatus of  claim 81 , wherein the program instructions comprise instructions for depositing the defect-mitigating insulating layer at (i) a location between an intermediate position within the electrochromic layer and the position of the electrode layer to which the electrochromic layer is in most direct electrical communication or (ii) a location between an intermediate position within the counter electrode layer and the position of the electrode layer to which the counter electrode layer is in the most direct electrical communication. 
     
     
       83. The apparatus of  claim 35 , further comprising a lithium deposition station containing a lithium target for depositing lithium on or within the layer of electrochromic material or on or within the layer of counter electrode material when the substrate is positioned in the lithium deposition station.